str1 = "hello world"
str2 = 'hello world'
str3 = '''hello
world'''
print(str1)
print(str2)
print(str3)
print('hel\'lo world') #\转义符
print('123----{0}--{1}---{2}'.format(4,5,6))
str4 = 'hello'
print(f'123---{str4}')

#f('{变量名}') 或 F('{变量名}')  格式化
for i in range(0,101,2):
    print("==================开始下载=================")
    if i ==100:
        print("下载完成")
    else:
        str5 = "*"*(i//2)+'.'*((100-i)//2)
        print(f'{i}%[{str5}]')
#
